Multimedia recording refers to a procedure in which the video and audio are recorded by a video camera and stored on a storage medium. Current video cameras, mobile phones provided with a camera, etc. are provided with such a function.
For use on a communication network device, the data obtained by a video camera can be collected via a communication terminal, and content of the data obtained by a video camera can be stored in a storage device of the communication network. In this way, functions of multimedia mailbox messages, multimedia video storage, etc. can be realized.
The above service is also required to be realized in a network device with the architecture in which media resource processing is separated from media controlling, such as WCDMA IMS (IP Multimedia Subsystem). However, when the H.248 protocol is employed as a control interface, the H.248 protocol has to be extended.
The H.248 protocol is a protocol defined by the ITU-T SG16 Standards Organization and dedicated for controlling media resources, which is used to control media resource processor, such as a media gateway, a media server, etc.
An essential principle of the H.248 protocol is that various resources on a media resource processor are abstracted as terminals divided into physical terminals and temporary terminals. The physical terminal represents a physical entity that semi-persistent exists, such as a TDM timeslot. The temporary terminal represents a common resource that would be released after a use as requested temporarily, such as an RTP stream. Combinations of terminals are abstracted as context, and the relationship between terminals is described with a topology. Based on such abstractions, a call connection is actually an operation on the terminals and the context, which is accomplished via command requests and responses between a media recourse controller and a media resource processor. The commands include Addition, Modification, Deletion, Notification, etc. The command parameters, referred to as descriptors, are divided into Property, Signal, Event and Statistic. Service-related parameters are logically aggregated into a package which is an approach provided from the H.248 protocol for extension of protocol functions.
Media controllers obtain sets of codec capabilities of subordinate gateways of each other by exchanging messages, and during setting up a bearer channel, select a codec supported by the gateways on both ends as a codec format for a final bearer channel that has been set up. Such a process is a negotiation process about the bearer capability.
In the WCDMA IMS network, the architecture of a network for processing a media resource service is as shown in FIG. 1, where: an AS (Application Server) functional entity processes a service, and an operator provides a supported service through the AS which also has a new demand for the corresponding service on other network elements an S-CSCF (Serving Call Session Control Function) functional entity processes routing, that is, the S-CSCF functional entity forwards correctly a message sent from the AS to an MRFC (Multimedia Resource Function Controller), or routes correctly a message sent from an MRFC to another MRFC; the MRFC functional entity is responsible for controlling media resources, that is, according to a requirement of the AS, the MRFC functional entity selects an MRFP (Multimedia Resource Function Processor), and controls the processing of media resources; and the MRFP functional entity is responsible for processing the media resources, and accomplishes a media resource operation sent from the AS under the control of MRFC.
The SIP (Session Initial Protocol) protocol and the XML protocol or the SIP protocol and a protocol similar to the XML (VXML is one derived from XML) are used for interfaces between the AS, S-CSCF, and MRFC functional entities. An interface between the MRFC and MRFP functional entities is referred to as an Mp interface using the H.248 protocol, and an outward interface of the MRFP is referred to as an Mb interface. A user media stream is typically borne through the RTP protocol.
Only the functions of voice playing and recoding can be realized between an MRFC and an MRFP in the WCDMA IMS network, and an extension of the protocol needs to be implemented for multimedia recoding function. In the case of a fixed network where the H.248 protocol is used as a control protocol, the multimedia recoding function cannot be supported.